Date of Graduation


Document Type


Degree Type



School of Dentistry


Restorative Dentistry

Committee Chair

Matthew S Bryington

Committee Co-Chair

Bryan D Dye

Committee Member

Bryan Weaver


Objectives: To evaluate the retention of Locator R-TX (ZEST Anchors LLC, Escondido, CA USA), Locator (ZEST Anchors LLC, Escondido, CA USA) and GPS (Implant Direct Sybron International, LLC, California, USA) dental implant attachment systems on parallel and divergent implants after sixteen months of simulated cyclic wear.;Methods: 30 acrylic blocks representing mandibular arches were used. Two Locator R-TX, two Locator, or two GPS abutment analogs were placed parallel or with 10 degrees of divergence in each block. The associated housings were picked up in corresponding acrylic blocks with clear Orthodontic resin (Dentsply GAC, Islandia, NY USA). The black processing liners in each housing were replaced with either low retentive or 1.5lb retentive elements. An eyebolt was attached to each block so it could be attached to an INSTRON 5565 Universal Testing Machine (Instron, Northwood, MA USA). The acrylic blocks were repeatedly separated and reattached by hand for 2000 pulls. The retentive force needed for dislodgement was measured at pull 500, 1000, 1500 and 2000.;Results: The type of attachments (GPS, Locator, Locator R-TX) showed statistical significance. The number of pulls and the inter-implants angulation did not exhibit a statistical significance. The Locator attachment had 10.3 N more retention than the GPS and 3.6N more than the R-TX attachment.;Conclusions: After 2000 cycles of seating and unseating, the retention generated by Locator attachments was greater than other attachments and was not negatively affected by inter-implants angulation in the 0 to 10 degrees range.